Tensiometer



March 28, 1944. G. P. LEssMANN rs1-A1.

TENSIOMETER Filed Jan. 15, 1941 2 Sheets-Sheet l |NvENToRs flWITNEISSES! JMW ATTOR EY w I W March 2s, 1,944. G, R ESSMANN Em2,345,132

Patented Mar. 28, 1944 UNITED STATES PATENT GFFIC TENSIOMETER vaniaApplication January 15, 1941, Serial No. 374,506

(Cl. 265-L6) 1I) Claims.

Our invention relates, generally, to tensiometers, and, moreparticularly, to tensioning devices and indicating means for subjectinga strip of material to tension and indicating the degree of striptension as the strip passes between adjacent work devices.

In the operation of steel strip rolling mills, it is common practice tosubject the strip to tension as it extends between adjacent roll standsand/or between a roll stand and an adjacent roll by causing a tensioningroller to bear against and apply a transverse force to the strip.

Such tensioning rollers are usually arranged to be actuated by a singleoperating device which rigidly connects the two end bearings of thetensioning roller and thereby imparts the same movement to both ends oilthe tensioning roller. Means are also commonly provided for causing thestrip tension to vary with. the strip deflection so that the stripdeectionis a measure of the strip tension. Such a tensioning device isshown in the copending application of G. P. Lessmann, Serial No.252,934, led January 26, 1939, now Patent No. 2,250,540, issued July 29,1941.

Differences in the screw-down settings of the two ends of the reducingrolls results in a difierence of strip reduction from one side of thevstrip to the other, and, even though the desired total tension may beapplied tothe strip, all or most of the tension may be applied to oneside of the strip and there may be such an-unbalance ofthe strip tensionas to tear the strip at the point where the greatest tension is applied.

An object of our invention isfto provide a :strip tensioningY andtension indicating device which shall function to indicate Ythe totalstrip tension and the tension differential between the .two sides of thestrip, which shall function to' limit the tension differential topredetermined .adjustable amounts, which shall be simple in ccn-ystruction, Iand simple andv efficient inoperation.

These andY other objects and advantages of` the invention will beapparent from the following detailed description talsenV in connectionwith thel accompanying drawings, in which:

Figure- 1 -is a front elevation view,` partly in section, of atensiometer embodying thev principal features of our-invention, Y

Fig. 2 is a side-elevation view of theindicator actuatingmechanismassociated with the tensiometer of Fig. 1, Y

Fig. 3' is a front=elevationview-of the mecha-` nismshownlin Fig.2,`V

CII

Fig. 4 is a sectional View taken along the line IV-IV of Fig. 1,

Fig. 5 is an elevation view, partly in section, of an adjustablerelative displacement limiting coupling which is a part of the mechanismof Fig; 1,

Fig. 6 is a sectional View of the bearing mounting for the end of thetensioning roller of Fig. 1,

Fig. '7 is a diagrammatic representation of an indicating systemassociated with thetensiometer of Fig. 1.

Figs. 8 and 9 are sectional viewsA onl the lines VIII and IX of Fig. 1.

, 1n practicing the invention, a tensionroller I6 has its ends rotatablymounted on supporting members' I2 and I4 which are pivctally mounted andactuated by power units I6 and I8 to cause the tensioning roller toapply a transverse' force to the strip as it extends between adjacentroll stands of a strip rolling mill or between a roll stand and anadjacent reel to thus subject Vthe strip to tension. Spherical bearingmembers, a sectional view of one of which is showny in Fig. 6, anddisposed between the endsl ofthe tensioning roller and the supportingmembers I2 and I4 to permit freedom of independent movement of theseparate ends of the tensioning roller I0.

Tht strip deflecting movements of the separate ends of the tensioningroller I0 are'transmittedto a shaft 20 and a sleeve 22 concentrictherewith, respectively, and these movements are transmitted by theshaft and sleeve to an indicator actuating mechanism 24 disposed in acasing 26. The indicator actuating mechanism- 24 functions to actuateremote indicator actuating means such as synchro-tie transmitters inaccordance with the differential between Vthe deflections of the twoside portions ofthe strip by the tensioning roller and the `sum of thedeflections of the two side portions of the strip. An adjustablecoupling 28 disposed between the shaft 2li and the sleeve 22 functionsto limit the differential between the degrees of deflection of thev twoedge portions of the strip.

A remote indication system shown diagrammatically in Fig. '7 functionsto give anindicaj tion at a suitable remote point of thel diiferentialbetween the deeetions of the two edge portions of the strip and the sumof the deectionsof the two edge portions of the strip. K

Thevoperating parts of the `tensioning; device are mounted on bracketmembers Strand-32 which are connected by a beam member 34 Vand which areadjustably mounted on the-housings 35Y and 38 of a strip rolling mill orother worlcdevice,y

Considering the invention more in detail, the ends of the tension rollerI are supported by their respective supporting members I2 and I4 byspherical bearings, the details of the bearing associated with thesupporting member I4 being shownvinFig. 6. The bearing may comit prisean outer bearing member 40 having an inner spherical bearing surfacecooperating with a spherical bearing surface on the outer race 42 of aroller bearing unit. The rollers 44 of the bearing unit engage the outerrace 42 and the inner race 46, the inner race being attached to the endmember 48 of the tension roller I0. The bearings are held in place onthe supporting members I2 and I4 by means of cap members 50 and 52 asshown in Figs. 1 and 4.

The sleeve member 22 and the shaft 20 are rotatably supported on bracketmembers 54 and 56 which, in turn, are secured in any suitable manner tothe bracket members 30 and 32. The sleeve member 22 may be fixedlysecured to the roller supporting member I4 in any suitable manner-suchas by a key member I5 as shown in. Fig. 8 so that the movement of thesupporting member I4 by the power unit I8 will cause rotational movementof the sleeve member 22. Likewise, the shaft 20 may be secured by a keymember I3 to the supporting member I2 to provide rotational movement ofthe shaft 20 when the supporting member I2 is actuated by the power unitI6.

The power units I6 and I8, aV section of one of which is shown in Fig.`1, may comprise a cylinder member 58 having an extension 60 whichextends into a slot in the supporting member I4 and is pivotallyattached thereto by a pin member 62. The cylinder member 58 is actuatedby a coil spring 64 which reacts against a piston 66 mounted upon atubular piston stem 68 which extends through a cover member 'I0 of thecylinder 58. The piston stem 68 has bearing members I2 and 'I4 securedthereto by any suitable means such as by welding and these bearingmembers cooperate with knife edge bearing members I6 and I8 to supportthe piston stem on the shelf portion 80 of the bracket 32. A dampingcylinder 82 is secured toan extension of the piston stem 68 and has apiston member therein operated by a piston stem 84 secured to thecylinder 5B and operating in a damping uid to prevent too rapid motionof the tensioning roller.

The sleeve member 22 and the shaft 20 extend into the casing 26, asindicated in Figs. 2 and 3. An arm member 85 having a rack segment 88secured thereto is secured to the shaft 20 for rotation therewith. Anarm member 80 is secured to the sleeve member 22 for rotation therewithand has a shelf member 62 attached thereto. A motion transmitting devicesuch as a synchro-tie transmitter 94 is mounted upon the shelf member 92and has a shaft 06 upon which there is mounted a pinion 98 incooperative relation with the rack segment 88. A second rack segment |00is mounted upon theV arm member 86 A third arm member |02 is rotatablymounted upon the sleeve member 22 and has a rack segment1|04 thereon. Ashaft member |06 is rotatably mounted on the arm 80 and has mountedthereon gear members |08 and IiD cooperatively engaging the racksegments |08 and |04, respectively, the diameter of -the gear members|08 and' ||0 having the ratio of 2 to 1. A motion transmitting device II2 is mounted on the bracket 32-byfabracket I|4 and is operativelyconneoted to the rack segment |04 by means of a shaft member I|6 and agear member ||8 which engages the rack segment |04.

The motion transmitting devices 94 and II2 may be synchro-tietransmitters which are commonly known in the art connected withreceiving units |20 and |22, respectively, which' may be synchro-tiereceiver units and which operate indicator devices |24 and |26,respectively.

In the operation of the device, the spring member 64 exerts an upwardforce upon the operating arms I2 and I4 to cause the tensioning rollerI0 to bear against a strip of material as it extends between adjacentwork devices such as adjacent strip rolling mill stands, or a striprolling mill stand and an adjacent reel, to thus subject the strip totension. The tension to which the strip is subjected will be a functionof the position of the tensioning rcller I0 and the ldifferentialbetween the tension on the two edge portions of the strip, will causedifferent deflections of the two edge portions of the strip by thetension roller I0. The deflections of the two edge portions of the stripare a function of the angular displacement of the shaft 20 and thesleeve member 22 which are transmitted to the indicator actuatingmechanism 24.

The rotation of the shaft 20 will cause thhe arm 86 to rotate carryingwith it the rack segment 88 and transmitting its movement to the pinion98. The rotation of the sleeve 22 in the same direction will cause thearm 90 to rotate in the same direction carrying with it the pinion 98causing the pinion to rotate in the opposite direction to the rotationcaused by the movement of the rack 88 by the shaft 20. Thus the pinion98 and the position transmitting device 94 operated thereby will assumea position which'is a measure of the relative angular displacements ofthe shaft 20 and the sleeve 22 and the indication transmitted by theposition transmitting device 94 to the instrument |24 will be a functionof the differential tension across the width of the strip which' isacted upon by the tension roller I0. The scale of the indicating device|24 may accordingly be graduated in strip tension and the diiferentialstrip tension may be read directly therefrom.

The rotation of the shaft 20 will cause the rack segment |00 to drivethe gear member |08 which, in turn, will drive the gear member IIO andthe gear member ||0 will rotate the arm |02 through its engagement withthe rack segment |04. As the arm member 90 is rotated by the sleeve 22,it will carry with it both of the gear members |08 and IIO 'thus causingfurther displacement of the arm |02 by the engagement of the gear.member IIO with ,the rack segment |04 and the movement of the shaft |06with the arm 90.'

Thus it will be seen that, with the ratio of the diameters of the gears|08 and III) equal to 2 to 1, equal angular displacementsl of the arms86 and 90 will cause equal displacements of the arm |02 and that thedisplacement of the arm |02 will be proportional to the valgebraic sumof the angular displacements of the arms 86 and 90.

Thus the movement of the arm |02 will be proportional to the sum of theangular displacements of the shaft 20 and the sleeve`22 and thismovement will be transmitted through the gear member ||8` andthe motiontransmitting device] I2 to the indicator |26 which may be graduated toindicate the total tension on the stripA which is acted upon bytensioning roller I0.

The adjustable coupling 28, as shown in Fig. 5, is provided to limit therelative displacement of the shaft 20 with respect to the sleeve 22 andcomprises a sleeve member |28 secured to the shaft 20 by any suitablemeans such as a key |30 and having substantially V-shaped indentations|32 in one edge thereof. A sleeve member |34 having protuberances |36-extending i-nto and shaped similar to the indentations |32-is mountedfor rotation with the sleeve member 22 by a key member |38. It will beseen that the allowable relative angular displacement between the shaft26 and the sleeve 22 is controlled by the circumferential spacing of theedge portions |39 `and |40 of the sleeve. members |34 and |28respectively, and that this spacing may be adjusted by axially movingthe sleeve member |134.. The axial movemen-t of the sleeve member |34 isprovided by a collar member-IM threaded upon the sleeve 22 and coupledWith the sleeve member |34 by means of a collar` |42 which; has slidingengagement with circumferential slots in the sleeve member |34 and thecollar member |4|. A second collar member |44vserves asv a lockingmember -for theV collar member t4! to prevent rotation thereof. Thus astheV collar member |4| is rotated by its threaded engagement with thesleeve member 22, it will cause the axial movement ofthe sleeve member|34 to vary the spacing-between the surfaces |39` andk |40 to thus varythe limit of the relative angular displacement of the sleeve member 22in the shaft 26.

A suitable cover |46 for the adjustable tube 28 is secured to the sleevemember |28.

The tensioning device may be adjusted vertically by aV mechanismv whichcomprises brackets |48` and |53 secured to the mill housings. 36 and 38fromV which .thereA are suspended bolt members |52 and |54 which extendthrough bracket members' |66v and |58v which are, in turn,` secured tothe bracketmembers 3Q and 32. Members |63 and |62 bear upon thelbrackets |56and |58 and threadedly engage the -bolt members |52 and |54and maybe rotated by a handwheel E64. by means of worms |66 and |68which are-operated bythe handwheel |64 and which engage worm gears I T0and ,|'|2. The worm gears |13 and |72 are secured to and rotate themembers |63 and |62. After the device has been adjusted by the hand-Wheel |64, the brackets 3U and 32 are clamped to the mill housings 36and 38 by means of bolts |14, |16, |73 and |86 whichk are secured to themillhousings and,extend throug`h slots in the brackets 3S and 32. Agauge is provided for indicating the vertical position of the tensioningdevice and comprises a gauge scale |82 secured to the ,mill housing 36by means of a bracket |84 and cooperating witha mark |786 on the bracket30 to indicate. the relative position of the :bracket 3U andthe millhousingt. v t

Thus it will :be seen that we have provided a tensioning device for astrip rolling mill which shall function to subject the two edge portionsof a strip to tension in accordance with the strip deections and whichshall function to indicate the total tension on .thev strip and. thetension differential between the two edge portions of the strip.`

In. compliance with thev requirements of the patent statutes, lwe haveshown and described herein the-preferred embodiment of our invention. Itis to be understood, however, that the inventionA is not limited to theprecise construetion shown and described but is capableof Inodifcationby one skilled in the art, the embodiment herein shown being merely`illustrative of the principles of our invention.

We claim as our invention:

1. In a device for tensioning a strip of material as it extends betweenadjacent work devices, a tensioning roller disposed to bear against thestrip and thus subject it to tension by deflecting it from the linebetween the work devices, a supporting arm adjacent each end of saidtensioning roller, means rotatably mounting each end of the tensioningroller on its adjacent supporting arm, a sleeve member, means rotatablymounting said sleeve member in a position displaced from andsubstantially parallel with said roller, a shaft memberv substantiallyconcentric with and extending beyond said sleeve member, means securingone of said supporting arms to said sleeve member for rotationtherewith, means securing said other supporting arm to said shaft forrotation therewith, separate means for actuating said supporting arms tothereby cause said tensioning roller to apply a transverse deflectingforce to the strip and indicating means actuated by said sleeve memberand said shaft.

2. In a device for tensioning a strip of material as it extends betweenadjacent work devices, a tensioning roller disposed to bear against thestrip and thus subject it to tension by deflecting it from the linebetween the work devices, a supporting arm adjacent each end of saidtensioning roller, means rotatably mounting each end o-f the tensioningroller on its adjacent supporting arm, a sleeve member, means rotatablymounting said sleeve member in a position displaced from andsubstantially parallel with saidroller, a shaft member substantiallyconcentric with and extending beyond said sleeve member, means securingone of said supporting arms to` said sleeve member -for rotationtherewith, means securing said other supporting arm to said shaft forrotation therewith, separate means for actuating said supporting arms tothereby cause said tensioning roller to apply a transverse deectingforce to the strip,-said actuating means comprising means for varyingthe strip tension as a function of the degree of deflection of the stripand indicating means actuated by saidv sleeve member and said shaft.

3. In a device for tensioning a strip of material as it extends betweenadjacent work devices, a tensioning roller disposed to bear against thestrip and thus subject it to tension by deecting it from the linebetween the work devices, a supporting arm adjacent each end of saidtensioning roller, means rotatably mounting each end of the tensioningroller on its adjacent supporting arm, a sleevemember, a shaft member,means rotatablyvr mounting said shaft member in aposition displaced fromthe tensioning roller and substantiallyconcentric with andextending-beyond said sleeve member, means securing one of'saidsupporting-arms to said sleeve member for rotation therewith, meanssecuring said other supporting arm to said shaft member for rotationtherewith, and separate means for actuating said supporting arms tothereby cause said tensioning roller to apply a transverse deflectingforce to the strip, said actuating means comprising means for varyingthe strip tension as a function of the degree of deiiection of thestrip, and means. responsive to the degree of rotation of said sleevemember and `said shaft member.y for automaticallyidetermining: theAtotal. strip,.tensioni l and: lthe tension differential between the twoedge portions of the strip.

4. In a device for tensioning a strip of material as it extends betweenadjacent work devices, a tensioning roller disposed to bear against thestrip and thus subject it to tension by deecting it from the linebetween the work devices, a supporting arm adjacent each end of saidtensioning roller, means rotatably mounting each end of the tensioningroller on its adjacent supporting arm, a sleeve member, means rotatablymounting said sleeve member in a-position displaced from andsubstantially parallel with said roller, a shaft member substantiallyconcentric with and extending beyond said sleeve member, means securingone of said supporting arms to said sleeve member for rotationtherewith, means securing said other supporting arm to said shaft memberfor rotation therewith, separate means for actuating said supportingarms to thereby cause said tensioning roller to apply a transversedeiiecting force to the strip, and means responsive to the degree ofrotation of said sleeve member and said shaft member for automaticallydetermining the sum of the deflections and the difference between thedeflections of the two edge portions of the strip.

5. In a device for tensioning a strip of material as it extends betweenadjacent work devices, a tensioning roller disposed to bear against thestrip and thus subject it to tension by deecting it from the linebetween the work devices, a supporting arm adjacent each end of saidtensioning roller, means rotatably mounting each end of the tensioningroller on its adjacent supporting arm, a sleeve member, means rotatablymounting said sleeve member in a position displaced from andsubstantially parallel with said roller, a shaft member substantiallyconcentric with and extending beyond said sleeve member, means securingone of said supportingarms to said sleeve member for rotation therewith,means securing said other supporting arm to said shaft member forrotation therewith, separate means for actuating said supporting arms tothereby cause said tensioning roller to apply a transverse deectingforce to the strip, and means responsive to the degree of rotation ofsaid sleeve member and said shaft member for automatically determiningthe sum of the deflections and the difference between the deflections ofthe two edge portions of the strip, said deflection determining meanscomprising a first arm member and a second arm member secured to saidshaft member and said sleeve member respectively for rotation therewith,a first rack member secured to one of said arm members, a rst gearmember rotatably mounted upon the otherarminernber and disposed tooperatively engage said* racl;` member, a third arm member, meansmounting said-thirdarm member for rotation concentric with said shaftmember and said sleeve member, a second rack member secured to saidthird arm member, -a pair of gear members rotatably mounted on saidother arm member in driving relation with each other and each disposedin operative engagement with a different one of said rack members, meansresponsive to the movement of said flrst gear member for indicatingthediierential between the deiiections of the two edge portions of thestrip, and means responsive to the movement of'said third arm member forindicating the sum of the deflections of the two edge portions of thestrip.

6. In a devicefor tensioning a strip of material as'it extends betweenadjacent work devices, a

tensioning roller disposed to bear against the strip and thus subject itto tension by deflecting it from the line between the work devices, asupporting arm adjacent each end of said tensioning roller, meansrotatably mounting each end of the tensioning roller on its adjacentsupporting arm, a sleeve member, a shaft member, means rotatablymounting said shaft member in a p0- sition displaced from said rollerand substantially concentric with and extending beyond said sleevemember, means securing one of said supporting arms to said sleeve memberfor rotation therewith, means securing said other supporting arm to saidshaft member for rotation therewith, separate means for actuating saidsupporting arms to thereby cause said tensioning roller to apply atransverse deecting force to the strip, said actuating means comprisingmeans for varying the strip tension as a function of the degree ofdeflection of the strip, and means responsive to the degree of rotationof said sleeve member and said shaft member for automaticallydetermining the total strip tension and the tension differential betweenthe tWo edge portions of the strip, said tension determining meanscomprising a first arm member and a second arm member secured to saidshaft member and said sleeve member respectively for rotation therewith,a first rack member secured to one of said arm members, a first gearmember rotatably mounted upon the other arm member and disposed tooperatively engage said rack member, a third arm member, means mountingsaid third arm member for rotation'concentric with said shaft member andsaid sleeve member, a second rack member secured to said third armmemlber, a pair of gear members rotatably mounted on said other armmember in driving relation with each other and each disposed inoperative engagement with a different one of said rack members, meansresponsive to movement of said rst gear member for indicating thedifferential between the tensions on the two edge portions of the strip,and means responsive to the movement of said third arm for indicatingthe sum of the tensions on the two edge portions of the strip.

7. In a'device for tensioning a strip of material as it extends betweenadjacent work devices, a tensioning roller disposed to bear against thestrip and thus subject it to tension by deflecting it from the linebetween the work devices, a supporting arm adjacent each end of saidtensioning roller, means rotatably mounting each end of the tensioningroller on its adjacent supporting arm, a sleeve member, means rotatablymounting said Vsleeve member in a position displaced from andsubstantially parallel with said roller, a shaft member substantiallyconcentric with and extending beyond said sleeve member, means securingone of said supporting arms to said sleeve member for rotationtherewith, means securing said other supporting arm to said shaft memberfor rotation therewith, separate means for actuating said supportingarms to thereby cause said tensioning roller to apply a transversedeiieoting force to the strip, and means responsive to the degree ofrotation of said sleeve member and said shaft member for automaticallydetermining the sum of the deflectionsand the diierence between thedeflections of the two edge portions of the strip, said deflectiondetermining means comprising a first arm member and a second arm membersecured to said shaft mem-v ber and said sleeve member respectively forrotation therewith, a Vfirst rack member secured.

to one of said arm members, a first gear member rotatably mounted uponthe other arm member and disposed to operatively engage said rackmember, a third arm member, means mounting said third arm member forrotation concentric with said shaft member and said sleeve member, asecond rack member secured to said third arm member, a pair of gearmembers rotatably mounted on said other arm member in driving relationwith each other and each disposed in operative engagement with adiiferent one of said rack members, a first electrical positiontransmitting device mounted on said other arm member and connected inoperative relation with said rst gear member, a second electricalposition transmitting device disposed to be operated by said third armmember, first and second electrical position receiving means connectedin cooperative circuit relation with said rst and second electricalposition transmitting devices, and indicating means actuated .by saidrst and second receiving means for indicating the differential betweenthe deflections of the two edge portions of the strip and the sum of thedeflections of the two edge portions of the strip respectively.

8. In a device for tensioning a strip of material as it extends betweenadjacent work devices, a tensioning roller disposed to `bear against thestrip and thus subject it to tension by deiiecting it from the linebetween the work devices, a supporting arm adjacent each end of saidtensioning roller, means rotatably mounting each end of the tensioningroller on its adjacent supporting arm, a sleeve member, a shaft member,means rotatably mounting said shaft member in a position displaced fromthe roller and substantially concentric with and extending beyond saidsleeve member, means securing one of said supporting arms to said sleevemember for rotation therewith, means securing said other 'supporting armto said shaft member for rotation therewith, separate means foractuating said supporting arms to thereby cause said tensioning rollerto apply a transverse deecting force to the strip, said actuating meanscomprising means for varying the strip tension as a function of thedegree of deiiection of the strip, and means responsive to the degree ofrotation of said sleeve member and said shaft member for automaticallydetermining the total strip tension and the tension dierential betweenthe two edge portions of the strip, said tension determining meanscomprising a first arm member and a second arm member secured to saidshaft member and said sleeve member respectively for rotation therewith,a first rack member secured to one of said arm members, a rst gearmember rotatably mounted upon the other arm member and disposed tooperatively engage said rack member, a third arm member, means mountingsaid third arm member for rotation concentric with said shaft member andsaid sleeve member, a. second rack member secured to said third armmember, a pair of gear members rotatably mounted on said other armmember in driving relation with each other and each disposed inoperative engagement with a dierent one of said racl members, a rstelectrical position transmitting device mounted on said other armmemberv and connected in operative relation with said first gear member,a second electrical position transmitting device disposed to be operatedby said third arm, rst and second electrical position receiving meansconnected in cooperative circuit relation with said first and secondelectrical position transmitting devices, and indicating means actuatedby said iirst and second receiving means for indicating the differentialbetween the tensions on the two edge portions of thelstrip, and the sumof the tensions on the two edge portions of the strip respectively.

9; In a device for tensioning a strip of material as it extends betweenadjacent work devices, a tensioning roller disposed to bear against thestrip and subject it to tension by deecting it from the line between thework devices, separate actuating means for moving each end of saidtensioning roller to cause the tensioning roller to apply a transversedeilecting force to the strip, and mutually cooperating stop meansmounted upon the separate actuating means and so disposed as to limitthe strip defiecting motion of either end of the tensioning roller withrespect to the other end to thereby limit the deection differentialbetween the two edge portions of the strip to predetermined adjustableamounts.

10. In a device for tensioning a strip of material as it extends betweenadjacent work devices, a tensioning roller disposed to bear against thestrip and thus subject it to tension by deecting it from the linebetween the work devices, two separate rigid support members eachdisposed adjacent a dilerent end of said tensioning roller and eachmounted adjacent one end thereof for independent rotational movementabout a common axis, means rotatably mounting each end of said roller onits adjacent support member intermediate the ends thereof, separateactuating means pivotally attached to the free ends of the supportmembers for rotating each of said support members about the common axisto therebypcause said tensioning roller to apply a transversedei'lecting force to the strip, said actuating means comprising -meansfor varying the strip tension as a function of the degree of deection ofthe strip, and means including electrical position transmittingapparatus mechanically actuated by the support members and in accordancewith the relative rotational movements thereof and electrical positionreceiving apparatus responsive thereto for indicating the diierence inthe degree of deflection of the two side edges of the strip to therebymeasure the tension differential between said two side edges.

, GERHARD P. LESSMANN.

PAUL C. LOTTES.

